The first thing you should know is that I have never studied Italian, much as I’d like to. However, just from being in Italy over the years, I have become quite fluent in Menu Italian. Did you know that biscotti is plural? If you have the willpower to eat only one, you will crunch on a biscotto. But who can eat only one?
Have you ever tagged a wall? (Tsk tsk.) If you made only one mark, you created a graffito. Graffiti is when you (or Banksy) paint a large creation containing many letters and figures. If caught, you’d have to confess, “These graffiti were my creation. And that graffito over there also was mine.” Plural vs. singular.